What type screen does the Lumia 950xl have capacitive or resistive?

Rough rule of thumb:
Resistive Screens feel "soft" or squishy. They have to be as they work by you pressing one layer of the screen down into another layer where a mesh of wires lays, making contact and telling the screen where it has been pressed.
You can activate/use these screens with literally anything you can find to press against them.

Capacitive Screens feel "hard", and are almost always glass covered. These work by detecting the change in capacitance across the screen's surface as the human body has a different capacitance than the air. Technically, these don't even require you to touch them, a close hover of your finger will suffice.
You can only activate/use these screens with certain materials, typically rubber or things like that.